The most common power source for non-air breathing engines or motors such as those in unmanned undersea vehicles (UUVs), satellites, lunar bases, and unmanned aerial vehicles (UAVs), are conventional batteries. However, conventional batteries have a low energy density and, thus, lack sufficient energy capacity for many desirable applications. The few types that may provide sufficient energy capacity, such as lithium thionyl chloride, are cost prohibitive.
The solid oxide fuel cell (SOFC) has been explored as a potential power source to increase endurance of electrical power systems in non-air breathing applications, which may assist in extended missions required of UUVs. A solid oxide fuel cell system utilizing hydrogen may be compact and lightweight, and have no major moving parts. Moreover, readily available catalyst materials such as platinum group metal or alloy may be used in the solid oxide fuel cell. Since SOFCs do not involve combustion, in ideal conditions they may be used to generate electricity with much higher reliability than conventional batteries. This is because they are simple, highly efficient, tolerant to impurities, and can at least partially reform hydrocarbon fuels internally.
To achieve even greater efficiency, medium sized and larger solid oxide fuel cells have been combined with gas turbines. The solid oxide fuel cells may be pressurized and the gas turbine produces electricity from the extra waste thermal energy produced by the fuel cell.
However, compressed and/or cryogenic hydrogen and oxygen are often required to feed a solid oxide fuel cell, resulting in excessively heavy containment and/or complex and heavy apparatus for obtaining and insulating cryogenic temperatures.
In view of the above, there is a need in the art for methods and systems for producing hydrogen and oxygen for power generation using solid oxide fuel cells.